This disclosure relates generally to the detection of eye and head movement. More particularly, but not by way of limitation, this disclosure relates to techniques for detecting pupil location and the use of that information, and a head model, to track gaze.
It has recently been noted that three dimensional (3D) head tracking using a video sequence, or pose estimation using multiple images is an essential prerequisite for robust facial analysis and face recognition. Eye tracking often forms the basis of these operations and may be thought of as the process of electronically locating the point of a person's gaze, or following and recording the movement of the person's point of gaze. In practice, eye tracking is provided by locating and tracking corneal reflections from an applied light source. Because infrared or near-infrared light is not perceivable by the human eye, it is often used as the light source; infrared or near-infrared light passes through the pupil but is reflected by the iris, generating a differentiation between the pupil and the iris.